An interesting Edge article by Michael Gazzaniga ponders the questions of whether humans brains are unique among animals and, if so, what makes them unique. Are the neurons in human brains different from those in other animals? Is the wiring different? Is it just the size of the brain that matters? Do comparative neuroanatomy studies shed light on whether or not findings from rat and monkey brains can be extrapolated to human brains? Most interesting of all are recent genetic findings that reveal unique changes appearing at key points in our cultural evolution 37,000 years ago with the rise of modern humans and 5800 years ago with the rise of agriculture. There are also signs of continuing accelerated evolution in genes responsible for brain structure in humans. All of this is particularly interesting when considered in relation to the attempts to replicate human mental capabilities in robots. Michael Gazzaniga is professor of Psychology and directory of the SAGE Center for the Study of the Mind at the University of California Santa Barbara.